I don't think you're a liar, but the problem is that cats retract their claws when they walk.
Well, let's just say that you are talking about something I've never seen, and I've had many kitty paw prints on my cars through the years.
Both of y'all are talking in the general "shouldn't ought to happen" sort of vernacular. I'm telling you that I've seen it. I'm not denying it doesn't happen every time, and I sure won't say your precious kitty does it.
But it might well be that the cats you've seen aren't feral. I can't say that the cats I've seen doing the scratching have been feral, but that could be a factor in their claws hanging out. The one that I witnessed pulling up the most paint was actually a "domesticated" roamerd being chased up a car by a dog--it leapt from the ground all the way up to the car top, and the dog ate door, and the cat just barely stopped before falling off the other side because the top was waxed nice. But there was one nice paw-sized set of gashes and a quarter sized nick out of the paint where they first went in on the top of that car.
But it was funny to watch--'cause it wasn't my car.
I assure you it can and does happen. We had feral cats all over a neighborhood I used to live in near McLean VA's downtown, and they'd get under and on cars to warm up in the spring and fall. My roommate drove a classic car at that point, and it was all scuffed up with nail marks on the hood and roof after we moved there. Where their nails go when they're walking is evidently different from where they go when they're warming up.